Process and apparatus for making nondetonating gasoline



e F. w. SULLIVAN, JR., ET AL PE KOGESS AND APPARATUS FOR MAKING NONDETONATING GASOLINE Filed Jan. 15, 1932 Patent 5, m3

PROCESS it AIPATUS FOR NDNDETONATING GASO =l Frederick W. Sullivan, Jr., and. Wander-veer Voorhees, Hammond, Ind, assignors to Standand Oil Chicago, BL, a corporation of Indiana Application January 15,

11 Claims.

This invention relates to processes of preparing hydrocarbon compounds of lead and it comprises processes wherein a hydrocarbon, for example, ethane, propane, butane or hexane, is decomposed by the action of a silent electric discharge, to liberate free alkyl radicals such as methyl, ethyl, propyl or higher alkyl radicals and these reaction products are caused to combine with metallic lead whereby lead-alkyl compounds are formed.

Hydrocarbon compounds of lead, such as tetra ethyl lead, have been known for a number of years and are, at the present time, used in great quantities as knock-suppressing substances in motorfuels. In general, these lead-alkyl compounds are prepared by reacting an alkyl chloride or bromide with a. lead alloy such as an alloy of sodium and lead. There are a number of other ways of making lead alkyl compounds all of which in general require the use of an, alkyl chloride. These methods are expensive and a way to prepare alkyllead compounds directly from hydrocarbons and metallic lead would be more desirable.

We have now found that hydrocarbon compounds of lead can be obtained directly from lead and hydrocarbons if the hydrocarbons are decomposed by the silent electric discharge in the presence of metallic lead. The silent electric discharge, when allowed to act on hydrocarbons such as ethane, propane, butane, hexane, and olefins such as ethylene, propylene, and higher members of the series, will decompose such hydrocarbons giving appreciable quantities of free alkyl radicals in the decomposition, products. These free alkyl radicals have a relatively short life since they tend to combine with each other rapidly. However, we have found that, if such free radicals are formed in the presence of metallic lead, reaction occurs between the radicals and the lead and lead-alkyl compounds are obtained. This reaction is almost instantaneous and gives acceptable yields of lead-alkyl compounds.

On the appended single sheet of drawings we have illustrated one convenient way of carrying out our process.

In the drawing, an electrical glow discharge or silent electric discharge reactor is indicated by numeral 1. It is constructed of a dielectric tubular element 2 generally made of glass, quartz or similar non-conductor of electricity, within which is electrode element 3 connected by lead 4 to insulated plug 5 and a source of high tension electricity, 6.

Surrounding the dielectric element 2 and con- 1932. Serial No. 586,918

centric therewith is electrode '1 which may be constructed of metal or other conducting material and which is preferably lined with a lead lining indicated by 8. An annular space 9 permits the flow of gases between this latter electrode and the dielectric surface. Electrode 7 is connected to the source of high tension current by the metallic structure of the outer shell of the reactor as shown.

The electrode 7 is constricted into gas outlet 10 leading to manifold 11 which may serve to unite a plurality of reactors. The reactor is also connected by inlet 12 to an inlet manifold 13 and vapor inlet 14.

Manifold 15 is connected to a source (not shown) of metallic lead highly dispersed in a suitable carrier gas. Such a fog of lead can be obtained by arcing lead electrodes in a current of hydrogen gas or other inert gaseous medium. Conduit 16 serves to connect the reactor with manifold 15.

Conduit 17 leads from outlet manifold 11 to cooler 18 and thence to pipe 19 and scrubber 20. This scrubber may be constructed inany conventional manner which will provide adequate contact between a scrubbing liquid and vapors. For example, it may be equipped with bafiie plates, bubble trays or the like. Pipe 21 connects the lower point of scrubber 20, to pump 21a and evaporator tower 22. Heat may be supplied to the base of evaporator 22 by any suitable means, as for example, by steam coil 23. The bottom of evaporator 22 is connected by line 24 to cooler 25 which discharges byline 26 into the top of scrubber 20. Pump 24a serves to pump scrubbing liquid back to scrubber 20.

Line 27 leading from the top of scrubber 20 connects with vacuum pump 28 suitably designed for maintaining a sub-atmospheric pressure on the system. The outlet from pump 28 may lead through vent valve 29 or through valve 30 intoline 31 leading to reactor inlet 14.

The top of evaporator 22 is connected by line 32, to the condenser 33 and receiver 34. The vapor outlet of receiver 34 is connected through valve 35 to line 27 leading to vacuum pump 28. Liquid collected in the receiver is indicated by gage glass 36 and maybe withdrawn through outlet valve 37.

In the operation of the apparatus shown on the drawings, hydrocarbon vapors, such as ethane, propane, butane, hexane, or the olefins, such as propylene, are passed into the reactor 1 through inlet 12. These vapors may come from any suitable source or may in part be products recycled from a latter stage of the process, as will be more fully explained. All that is re quired is that the hydrocarbons be of such nature that, when subjected to the silent electric discharge, they decompose with the liberation of free radicals.

The gaseous hydrocarbons pass into and through space 9 between lead lining 8 (on electrode 7), and dielectric 2 where they are subjected to the silent electric discharge occurring within this space. An impressed voltage of about 25,000 at 500 cycles is a satisfactory current to use. Under these conditions, decomposition of the hydrocarbons is rapid and the free alkyl radicals thus formed unite at once with the metallic lead lining 8 to form lead-,alkyl compounds.

The system being under reduced pressure due to vacuum pump 28, flow of gas through the system is rapid and reaction products quickly pass from the reactor to cooler 18 and thence to scrubber 20. An absolute pressure of about 10 pounds suffices to create a rapid flow of gas through the system and. it is advantageous to withdraw reaction products soon after their formation. This not only increases the productive capacity of the apparatus but also insures that no substantial decomposition of the formed alkyl compounds will occur. Moreover, when normally liquid hydrocarbons are used, the absolute pressure may be reduced to keep such hydrocarbons in the gaseous state at temperatures well below their normal boiling points.

In cooler 18, the temperature of the reaction products is brought down to about 20 C. or below, the actual amount of cooling depending upon the nature of the hydrocarbon being used.

The cooler is for the purpose of lowering the temperature of the reaction products to such degree that in the subsequent scrubbing operation, all lead-alkyl compounds will be retained in the scrubbing liquid. These alkyl compounds are rather volatile materials. The cooler also prevents any decomposition of the lead compoundsshould they be at or near their decomposition temperature on leaving the reactor. The cooler can be dispensed with if desired so long as the scrubber is operated at a temperature below the decomposition temperature of the lead compounds and low enough to ensure complete retention of the lead compounds.

Passing from the cooler, the reaction products enter the scrubber through conduit 19. In the scrubber, the gaseous products are scrubbed with a suitable hydrocarbon oil. Any liquid hydrocarbon will suffice so long as it dissolves the lead compounds, and, in the modification shown,has a boiling point higher than the lead compounds. Heavy hydrocarbon distillates such as kerosene, gas, oil, etc. are suitable. In the arrangement of apparatus shown, the scrubbing liquid is obtained from evaporator 22 as will be explained. Liquid flowing from the bottom of scrubber 20 is passed to evaporator 22 wherein the volatile lead-alkyl compounds are vaporized, or fractionally distilled. The volatile compounds pass out of the evaporator through line 32 to condenser 33 and thence to receiver 34 from which they may be withdrawn through outlet 37. Residual liquid in evaporator 22 is withdrawn therefrom, cooled in cooler 25, and sent back to scrubber 20.

When using ethane, propane, butane, or other lower members of the aliphatic or olefin hydrocarbon series, the undecomposed hydrocarbons leaving reactor 1 are not retained in the scrubbing liquid to any great extent and these pass from the top of the scrubber through outlet 2'7 and are recycled back to the reactor by pump 28, line 31 and line 14. In like manner, any uncondensed gases in receiver 34 are sent back to the reactor as shown on the drawing.

The foregoing description is particularly applicable when normally gaseous hydrocarbons are If norused as the source of alkyl radicals. mally liquid hydrocarbons, such as hexane, are used, it is advantageous to by-pass the reaction products from cooler 18 directly to the evaporator 22. In this case, hexane undecomposed in the reactor, and lead compounds formed therein, are condensed to liquid in cooler 18. The resulting solution is then passed directly to evaporator 22 by line 38. In the evaporator, the solution is fractionated and hexane vapors returned to the system. The lead-alkyl products may be withdrawn through outlet 39. V

In our process, however, it is more advantageous to use volatile hydrocarbons, such as ethane, propane and butane because the condensed reaction products collected in receiver 34 then consists almost wholly of the desired alkyl compounds. Normally liquid hydrocarbons tend to give a product admixed with appreciable quantities of undecomposed hydrocarbons. Such a mixture, however, can be added to gasoline for knock-suppressing purposes, and it is not necessary that the lead compounds be isolated in a pure state.

Instead of using hexane vapors we can use ordinary gasoline vapors as the hydrocarbon material introduced into the reactor and when this is done, we obtain a liquid condensate flowing from cooler 18 which consists of undecomposed gasoline containing lead compounds in solution. In other words, in this modification of our process. we obtain a fuel containing a knock-suppressing agent derived directly from metallic lead. Should the concentration of dissolved lead compounds be too low for practical purposes, we can partially fractionate the gasoline solution in evaporator 22 so as to increase the lead content in the gasoline, vaporized gasoline being returned to the system in the manner described. When the quantity of lead-alkyl compounds in the gasoline is adequate for knock-suppressing purposes, we can by-pass the gasoline solution from the cooler directly to the receiver 34 by way of conduit 19a.

As shown on the drawings reactor 1 is provided with an inlet 16 for the introduction of lead in addition to that of lead lining 8. Such added lead is best in the form of fine lead particles dispersed as a mist or fog in an inert gaseous vehicle such as hydrogen. Such a dispersion can be prepared by arcing lead electrodes in a flowing current of hydrogen gas. However, the use of an ordinary lead'lining in the reactor is sufficient for most purposes. When most of the lead has reacted, the lining can be replaced readily. A plurality of reactors,.connnunicating with manifolds 13, 15 and 11 is desirable because the lead lining in any reactor can be renewed without rendering the process discontinuous. I

Having thus described our invention, what we claim is:

1. The process of preparing hydrocarboncompounds of lead which comprises establishing a silent electric discharge, in the presence of metallic lead, within a body of a vaporized byalkyl 2. The process of preparing hydrocarbon com-' pounds of lead which comprises establishing a silent electric discharge, in the presence of metallic lead, within a body of hydrocarbon gas of the type yielding free alkyl radicals or decomposition.

3. The process of preparing a hydrocarbon liquid containing organic compounds of lead dissolved therein which comprises decomposing a hydrocarbon by a silent electric discharge in the presence of metallic lead, the hydrocarbon being one which yields free alkyl radicals on such de composition, whereby hydrocarbon compounds of lead are formed, and then condensing the reaction products.

4. The process of preparing a hydrocarbon liquid containing organic compounds of lead dissolved therein which comprises decomposing a hydrocarbon gas by a silent electric discharge in the presence of metallic lead, the hydrocarbon being one which yields freealkyl radicals on such decomposition, whereby hydrocarbon compounds of lead are formed, and then condensing the reaction products.

5. The process of preparing hydrocarbon compounds of lead which comprises establishing a silent-electric discharge within a body of hydrocarbon gases of the type yielding free alkyl radicals on decomposition and in the presence of metallic lead, cooling the reaction products, scrubbing the reaction products to remove the hydrocarbon compounds of lead from the gaseous mixture and then separating the hydrocarbon compounds of lead from the scrubbing liquid.

6. A process of preparing hydrocarbon compounds of lead which comprises establishing a silent electric discharge within a body of hydrocarbon gas of the type yielding free alkyl radicals on decomposition, and in the presence of metallic lead, cooling the resulting gaseous reaction products, scrubbing them with a solvent for the lead compounds, -fractionating with scrubbing liquid containing the lead compounds to separate the lead compounds therefrom, recycling the scrubbing liquid to scrub further quantities of gaseous reaction products and recycling undissolved reaction products to the silent electric discharge.

'7. An apparatus for the preparation of hydrocarbon compounds of lead comprisinga device for the production of a silent electric discharge, means to introduce hydrocarbon vapors therein,

means to maintain metallic lead within the zone of the silent electric discharge in said device, and means to separate hydrocarbon compounds of lead from the reaction products flowing from said device.

8. An apparatus for the production of hydrocarbon compounds of lead comprising a silent electric discharge device, means to introduce hydrocarbon vapors therein, means to maintain a body of metallic lead in the zone of the silent electric discharge occurring within said device, a scrubber connected to the silent electric discharge device to scrub reaction products formed therein and an evaporator to separate scrubbing liquid from the lead compounds dissolved therein.

9. An apparatus for the production of hydrocarbon compounds of lead comprising a silent electric discharge device containing metallic lead within the zone of the electric discharge therein, means to introduce hydrocarbon vapors in said device, a cooler operatively connected to said device to cool reaction products flowing therefrom, a scrubber operatively connected to said cooler to scrub reaction products leaving said cooler and to absorb lead compounds therein,-

an evaporator connected to the scrubber, means to conduct scrubbing liquid from said evaporator to top of said scrubber, means to cool and condense vapors leaving said evaporator, and means to conduct undissolved vaporous products leaving the top of the scrubber to the silent electric discharge device.

10. The process of preparing hydrocarbon compounds of lead which comprises decomposing vaporized hydrocarbon material by means of a silent electric discharge, said material being of the type yielding free alkyl radicals on such decomposition, and immediately contacting the products of such decomposition with metallic 'lead whereby the free alkyl radicals in said products combine with the lead to form hydrocarbon compounds of lead.

11. The process of preparing hydrocarbon compounds of lead which comprises decomposing hydrocarbon gas by means of a silent electric discharge, said gas being of the type yielding free alkylradicals on such decomposition, and immediately contacting the products of such decomposition with metallic lead whereby the free alkyl radicals in said products combine with the lead to form hydrocarbon compounds of lead.

FREDERICK w. SULLIVAN, JR. VANDERVEER VOORHEES. 

